portability and return

[Eligiusz Narutowicz]

Re: portability and return

"Bill Cunningham" <nospam@nspam.c omwrites:

"Peter Nilsson" <airia@acay.com .auwrote in message
news:3222fc05-7aee-4eb3-b874-eb55981751dd@v2 6g2000prm.googl egroups.com...

>Bill Cunningham wrote:

>>I have heard that return -1 is not portable.

>>
>Presumably you're talking about the return value from main()?

>
Yes. Would return -1 from a function other than main be ok? I'm guessing
no but I thought I'd ask.
>
Bill

You are for sure trolling. Please stop.

[Mark McIntyre]

Re: portability and return

Eligiusz Narutowicz wrote:

"Bill Cunningham" <nospam@nspam.c omwrites:

>(stufff)

You are for sure trolling. Please stop.

No, in fact Bill has some learning difficulty as far as we can discern.
--
Mark McIntyre

CLC FAQ <http://c-faq.com/>
CLC readme: <http://www.ungerhu.com/jxh/clc.welcome.txt >

[Eligiusz Narutowicz]

Re: portability and return

Mark McIntyre <markmcintyre@s pamcop.netwrite s:

Eligiusz Narutowicz wrote:

>"Bill Cunningham" <nospam@nspam.c omwrites:

>>(stufff)

>
>

>You are for sure trolling. Please stop.

>
No, in fact Bill has some learning difficulty as far as we can
discern.

This is impossible. How can anyone at this stage ask if a normal "int"
function can return -1 and then guess that it can not?

[Mark McIntyre]

Re: portability and return

Eligiusz Narutowicz wrote:

Mark McIntyre <markmcintyre@s pamcop.netwrite s:
>

>Eligiusz Narutowicz wrote:

>>"Bill Cunningham" <nospam@nspam.c omwrites:
>>>(stufff)

>>

>>You are for sure trolling. Please stop.

>No, in fact Bill has some learning difficulty as far as we can
>discern.

>
This is impossible. How can anyone at this stage ask if a normal "int"
function can return -1 and then guess that it can not?

Suggest you find out what "learning difficulties" means.

[Eligiusz Narutowicz]

Re: portability and return

Mark McIntyre <markmcintyre@s pamcop.netwrite s:

Eligiusz Narutowicz wrote:

>Mark McIntyre <markmcintyre@s pamcop.netwrite s:
>>

>>Eligiusz Narutowicz wrote:
>>>"Bill Cunningham" <nospam@nspam.c omwrites:
>>>>(stufff)
>>>
>>>You are for sure trolling. Please stop.
>>No, in fact Bill has some learning difficulty as far as we can
>>discern.

>>
>This is impossible. How can anyone at this stage ask if a normal "int"
>function can return -1 and then guess that it can not?

>
Suggest you find out what "learning difficulties" means.

I know what learning difficulties means. Please do not be so rude. But I
refuse to believe that someone who can get on usenet and post such
questions does not know what a signed int is for returning from a
function. It seems incredible. If he really is slow then he needs to be
elsewhere than this group and perform a proper tutorial or course.

[Richard Tobin]

Re: portability and return

In article <g0f0fq$69o$1@r egistered.motza rella.org>,
Eligiusz Narutowicz <eligiuszdotnar u@hotmail.comwr ote:

>This is impossible. How can anyone at this stage ask if a normal "int"
>function can return -1 and then guess that it can not?

If you look at the rest of the thread you will see that this is not
what he meant: he just expressed himself badly. He really wanted to
know if calling exit(-1) from functions other than main was just
as unportable as returning -1 from main.

-- Richard



--
:wq

[Mark McIntyre]

Re: portability and return

Eligiusz Narutowicz wrote:

Mark McIntyre <markmcintyre@s pamcop.netwrite s:
>

>Eligiusz Narutowicz wrote:

>>Mark McIntyre <markmcintyre@s pamcop.netwrite s:
>>>
>>>No, in fact Bill has some learning difficulty as far as we can
>>>discern.

....

>>This is impossible.

....

>Suggest you find out what "learning difficulties" means.

>
I know what learning difficulties means.

Good. Then perhaps you could consider how on earth you can possibly know
what is possible and impossible for someone you've never met?

Please do not be so rude.

*shrug*. It wasn't rude, but if you want to consider it so that's your
prerogative.

But I
refuse to believe that someone who can get on usenet

I can't help what you believe. I'm posting the facts as we know them and
have observed from Bill's posts here over the last several years.

Enough, no more - tis not so sweet now as it was before.

[Eligiusz Narutowicz]

Re: portability and return

Mark McIntyre <markmcintyre@s pamcop.netwrite s:

Eligiusz Narutowicz wrote:

>Mark McIntyre <markmcintyre@s pamcop.netwrite s:
>>

>>Eligiusz Narutowicz wrote:
>>>Mark McIntyre <markmcintyre@s pamcop.netwrite s:
>>>>
>>>>No, in fact Bill has some learning difficulty as far as we can
>>>>discern.

...

>>>This is impossible.

...

>>Suggest you find out what "learning difficulties" means.

>>
>I know what learning difficulties means.

>
Good. Then perhaps you could consider how on earth you can possibly
know what is possible and impossible for someone you've never met?
>

>Please do not be so rude.

>
*shrug*. It wasn't rude, but if you want to consider it so that's your
prerogative.
>

>But I
>refuse to believe that someone who can get on usenet

>
I can't help what you believe. I'm posting the facts as we know them
and have observed from Bill's posts here over the last several years.
>
Enough, no more - tis not so sweet now as it was before.

Sigh ok. But considering how you answer some not so slow people I am
astonished who think he is retarded as opposed to a troll. Someone who
is capable of posting to usnet surely understands brackets and scope in
C by now? I find it troubling that he can not. If he really is so slow
then maybe there are better places for him to learning C.

[soscpd@terra.com.br]

Re: portability and return



Last time I get into this thread, Bill say that he know enough about
the subject(by May 13, 6:47 pm). Something like "Thanks very much.
That answers my question completely".

Maybe one should create a new group called
comp.moderated. only.and.just.o nly.std.and.wiz .c

Regards
Rafael

[santosh]

Re: portability and return

Bill Cunningham wrote:

>
"Richard Tobin" <richard@cogsci .ed.ac.ukwrote in message
news:g0d3t6$26u i$1@pc-news.cogsci.ed. ac.uk...

>There's no problem returning -1 from main() either, as far as the C
>program is concerned. All that's undefined is how the "host
>environment" - the shell or operating system or parent program -
>interprets it. 0 (or EXIT_SUCCESS) indicates success. EXIT_FAILURE
>indicates failure. What anything else means depends on your system.

>
[snip]
>
That's what I am concerned with. How the host system will react.
What I
am really concerned with is what the standard says would run best on
any environment. I write small C programs in linux and I want to be
able to take the same source code to my windows system and compile it
there and get the same results. I am trying to get into the habit of
treating all code as development code so it would work in all host
environments.

In this case your best method (for now) is to use EXIT_SUCCESS and
EXIT_FAILURE as appropriate. This will work on all conforming
implementations . The only disadvantage is that there is only a single
abnormal termination status value. You probably won't need multiple
values for most programs, but if you do need them, then you may have to
place system specific code surrounded by #ifdefs.

[Bill Cunningham]

Re: portability and return


"Eligiusz Narutowicz" <eligiuszdotnar u@hotmail.comwr ote in message
news:g0f0fq$69o $1@registered.m otzarella.org.. .

This is impossible. How can anyone at this stage ask if a normal "int"
function can return -1 and then guess that it can not?

I don't believe that is what I asked. My post reads "portabilit y". Not
can an int type return an int. This is not so much about the return types of
C but portability of ending functions with success or failure on different
implementations . I have been told return -1 was "wrong" (not portable). I
wanted the voice of experience.

No tutorial has ever spoke to me about the reactions of different
implementations or this post would never have been made. I wanted to get
straight ending with success or failure with a function. I only post to clc
after I have
1) read a topic and am confused
2) and tried by trial and error and can't determine the straight answer by
trial and error.

I do have problems that are worsened by Klonopin. Read the side effects
of that. Confusion. But

I think you need to read the topic of a thread before guessing it's
about return types as per values other than the topic like success or
failure and its portability and the standard.

[Bill Cunningham]

Re: portability and return


[snip]

"Eligiusz Narutowicz" <eligiuszdotnar u@hotmail.comwr ote in message
news:g0f69i$8u4 $2@registered.m otzarella.org.. .

Sigh ok. But considering how you answer some not so slow people I am
astonished who think he is retarded as opposed to a troll. Someone who
is capable of posting to usnet surely understands brackets and scope in
C by now?

Brackets and scope? Yes I understand that. What does that have to do with
anything? It's "implmentations " and "portabilit y" that was the question. And
I never expected this thread to become this large. I thought 2-4 responses
would be made. I am grateful to those who have answered my question(s).

[snip]

[Bart]

Re: portability and return

On May 14, 10:03 pm, "Bill Cunningham" <nos...@nspam.c omwrote:

"Eligiusz Narutowicz" <eligiuszdotn.. .@hotmail.comwr ote in message
>
news:g0f0fq$69o $1@registered.m otzarella.org.. .
>

This is impossible. How can anyone at this stage ask if a normal "int"
function can return -1 and then guess that it can not?

>
    No tutorial has ever spoke to me about the reactions of different
implementations or this post would never have been made. I wanted to get
straight ending with success or failure with a function. I only post to clc
after I have
1) read a topic and am confused
2) and tried by trial and error and can't determine the straight answer by
trial and error.

This my approach to return in main():

(1) Completely ignore it
(2) If you /have/ to return a value, return anything (really, mostly
it doesn't matter)
(3) If someone/something complains, or it /does/ matter, return one of
EXIT_SUCCESS or EXIT_FAILURE, but those stick out like a sore thumb,
ruining the lines of my code (I don't like capitals much)

Your tutorial is taking the attitude that it's of little practical
importance to someone learning the language, which sounds right. There
are many more interesting things to worry about!

--
Bartc

[Keith Thompson]

Re: portability and return

"Bill Cunningham" <nospam@nspam.c omwrites:

"Eligiusz Narutowicz" <eligiuszdotnar u@hotmail.comwr ote in message
news:g0f0fq$69o $1@registered.m otzarella.org.. .

>This is impossible. How can anyone at this stage ask if a normal "int"
>function can return -1 and then guess that it can not?

>
I don't believe that is what I asked. My post reads "portabilit y". Not
can an int type return an int. This is not so much about the return types of
C but portability of ending functions with success or failure on different
implementations . I have been told return -1 was "wrong" (not portable). I
wanted the voice of experience.

[...]

I think your question was already answered, but I'll summarize.

A program can return a status code (of type int) to the host
environment (as it terminates) either by calling exit() with the
desired status as an argument, or by executing a return statement
within main(), returning the desired status. These two are
essentially equivalent. exit() can be called from anywhere, not just
from main().

The only portable status codes are 0, EXIT_SUCCESS, and EXIT_FAILURE.
Other values can be useful, but only in code intended for a particular
system.

Results returned by functions other than main() generally have
*nothing* to do with program status codes, so the advice to use 0,
EXIT_SUCCESS, or EXIT_FAILURE does not apply. The value you should
return from main() (or, equivalently, the value you should pass to
exit() is constrained by the host environment. The value you should
return from any other function is constrained by the requirements for
that function, something internal to your program.

Please feel free to ignore the following paragraph.

Returning a value from main and calling exit() with that same value
are *almost* equivalent. They can differ in an obscure and unlikely
scenario involving the atexit() function. They can also differ if you
call main() recursively, something that there's practically never a
good reason to do.

--
Keith Thompson (The_Other_Keit h) kst-u@mib.org <http://www.ghoti.net/~kst>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[Keith Thompson]

Re: portability and return

Bart <bc@freeuk.comw rites:
[...]

This my approach to return in main():
>
(1) Completely ignore it
(2) If you /have/ to return a value, return anything (really, mostly
it doesn't matter)
(3) If someone/something complains, or it /does/ matter, return one of
EXIT_SUCCESS or EXIT_FAILURE, but those stick out like a sore thumb,
ruining the lines of my code (I don't like capitals much)

Here's a better approach.

(1) Add ``return 0;'' immediately before the closing brace of your
main() function. Just think of it as part of the syntax.
(2) If you need to indicate failure, use EXIT_FAILURE. That's what
it's for. If you don't like capital letters, get over it.
(3) Consider using other values only if you need system-specific
status information.

--
Keith Thompson (The_Other_Keit h) kst-u@mib.org <http://www.ghoti.net/~kst>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"